1. Related Applications
There are no applications related hereto heretofore filed in this or any foreign country.
2. Field of Invention
Our invention relates generally to a a log delimbing device and more particularly to such a device that is of simple, rugged nature to function under Western logging conditions and has means to cut trees to predetermined length perpendicularly to their axis.
3. Background and Description of Prior Art
The economics of the logging industry, especially in the Western part of the United States, have become increasingly competitive and have generally tended to require increased mechanization of logging operations for the economic survival of its practitioners. Part of that mechanization has been directed to the delimbing and sectioning of cut trees. The instant invention provides a novel mechanism for this operation.
Many and various devices for delimbing and sectioning logs have heretofore come to be known. In the course of their development, however, they have become increasingly complex and sophisticated, so that in the modern day such devices come to a state wherein they violate their essence, and they merely increase the overall cost of logging rather than lessen that cost. Many such devices in the modern day provide a complete logging machine that cuts trees, delimbs them, cuts them into logs, decks them and handles the logs during and ancillary to all of these operations. Such machines normally will not replace ordinary bulldozers, heel booms and other mechanisms traditionally used in logging, so that ultimately they must be added as additional items to the already existing inventory of logging machinery merely to add to the total cost of capital invested in the operation. This additional investment oftentimes is in excess of $100,000 for such logging machines.
The instant mechanism seeks to provide a smaller, more durable machine that is adapted only to the delimbing of trees and the cutting of those trees into acceptable log lengths. In so doing, we seek to maintain the economy of the device by providing a mechanism that lessens rather than increases the overall logging cost by making use of other existing logging equipment to perform functions that it can economically perform rather than duplicating those functions of that other equipment.
As the sophistication of delimbing devices has increased, so proportionately has the mechanical complexity of such mechanisms. Many delimbers of the present day are self-powered and provide complex articulating frames or frame portions involving massive structures that require substantial amounts of power for their operation and locomotion. In logging in the Western part of the United States, the terrain on which the operation is conducted is generally mountainous, steep and rocky. Complex and compound delimbing devices are not at all amenable to efficient operation in this sort of environment. Commonly where such machines are self-powered, they have insufficient power to be mobile in all areas where needed and sufficient self-generated power cannot be economically provided. Again commonly, the complexly sophisticated and compounded devices do not have appropriate ruggedness and durability to be efficiently operable to fulfill their purposes, and commonly, they require so much substantial and costly maintenance as to make them uneconomical. The instant invention seeks to avoid these problems by providing a delimbing device on a trailer-type vehicle without means of self-propulsion. The device provides essentially a peripheral shell on which logs are contacted and supported so that only necessary operative elements are exposed and all other operative mechanism and structure is protected by this external shell. The vehicular carriage of the device is relatively small so that it may be readily moved with other logging apparatus, such as a bulldozer, heel boom or truck, and it also is compactly shaped so that its size and configuration allow it to be moved in almost any type of rocky, mountainous terrain where it may be required to operate.
Commonly in present logging practice, after a tree is cut and delimbed the entire tree trunk is too long to provide a merchandizable log, so that that tree trunk must thereafter be cut into logs of commercially acceptable lengths for merchandising. In general in the past, this sectionizing of a tree trunk into commercial length logs has been accomplished by manual operation, separate and apart from the delimbing process, though in some delimbers means have been provided in association with the device to sectionize a delimbed tree trunk. Generally in cutting a tree trunk to form commercial saw logs, it is desirable that the end cuts be substantially perpendicular to the axis of a log, or at least perpendicular to a lineal element of the trunk surface when tree taper be taken into account. This desired result has in the past presented problems when logs are cut by many delimbers, as commonly in the delimbing process a tree trunk, oftentimes more than one hundred feet in length, may assume differing attitudes relative to a delimber's frame and log support structure during different portions of the delimbing process, merely because of the nature or the delimbing device itself and of the delimbing process. In sectionizing such a tree trunk with a cutting device carried by the delimber, a cut has not necessarily been made perpendicular to the tree axis and if it is not, wood oftentimes may be wasted and the log ultimately cut is of less value.
Our invention seeks to resolve this problem by providing both a delimbing mechanism and a cutting mechanism that are pivotally mounted relative to their supporting frames, with additional linkage pivotally intercommunicating between the two mechanisms to maintain them constantly in a parallel relationship, with a log being delimbed extending substantially perpendicular therebetween at all times during the delimbing process. A typical chain saw is pivotally carried by the cutting mechanism to efficiently cut a tree trunk substantially perpendicular to its axis, at least within allowance for log taper. Prior art devices generally have not necessarily made such a perpendicular cut in sectioning trees and commonly have not used chain saw devices for making that cut.
Our invention resides not in any one of these features or improvements per se, but rather in the synergistic combination of all of them to provide the functions necessarily flowing therefrom as hereinafter more fully described and claimed.